Last month Google responded to a questionnaire about the policy sent by the French National Commission on Computing and Liberty (CNIL), acting on behalf of the European Union's national data privacy regulators.
However, the regulators were not satisfied. On Tuesday CNIL wrote again to Google CEO Larry Page, asking the company to elaborate on some of its answers.
"Given Google's extensive development and use of analytic tools, we are surprised that Google has not measured the impact of the campaign in order to assess efficiency of this information. Could you please confirm that you have no such information?" they asked in their letter Tuesday.
Google also failed to detail and explain the contents of the cookies it stores on users' computers, prompting the regulators to repeat that question.
Despite the answers provided by Google so far, CNIL considers it impossible to know how Google processes personal data, nor to determine who receives the data and why, it said in a statement. As such, it said, Google was not respecting its obligation under European law to inform the subjects of the data. In all, CNIL sought answers, or clarifications of answers, for almost half the 69 questions in the original questionnaire.
One issue bothering CNIL was the period for which Google retains data, or backups of that data, something it was unable to determine from Google's initial answers. Google told CNIL that backup tapes were encrypted and that the encryption keys were routinely deleted, but it did not say how often, or after what period. It asked Google to provide "the typical period that is used to renew the encryption keys for backup tapes and an upper-bound for the deletion or complete anonymisation of data."
CNIL officials were set to meet with Google representatives Wednesday to discuss the contents of the letter, among other issues.
Google representatives declined to comment on the discussions. The company has received CNIL's follow-up questions, and is reviewing them, a company spokeswoman said Thursday.
CNIL has given Google until June 8 to answer the second questionnaire. After that, Europe's privacy regulators will discuss the responses and, by mid-July, inform Google of any changes they think it needs to make to bring it into compliance with European data protection law.
Peter Sayer covers open source software, European intellectual property legislation and general technology breaking news for IDG News Service. Send comments and news tips to Peter at email@example.com.